EH72 FI - Subaru Industrial Power
Contents
1. E 24 8 8 DETONATION 45453444 Rae RR nates RD he Re e Han 24 8 9 ENGINE MISFIRE 5534292329999 93 GS Rude 25 8 10 DIAGNOSIS CODE CRUCE 26 9 MAINTENANCE AND 3 re 28 9 1 DAILY MAINTENANCE 2 0 0 2 eee 28 9 2 PERIODIC MAINTENANCE SCHEDULE 0 0000 ccc teens 28 9 3 SPARK ARRESTER OPTIONAL ii 0 54 2201000540004 r riir 943 EX 30 9 4 ENGINE STORAGE eue Ie Hae ea tae Ea a Rap UR eG wala eG 31 1 SPECIFICATIONS EH72 Fl Air Cooled 4 Stroke V Twin Cylinder Horizontal shaft OHV Gasoline Engine Number of Cylinders Bore X Stroke 2 84 X 65 3 31 X 2 56 Displacement ml cu in 720 43 9 Compression Ratio 8 1 Continuous Output kW HP r p m 14 9 20 0 3600 Net 17 9 24 0 3600 Maximum Output kW HP r p m Gross 19 4 26 1 3600 20 9 28 0 4000 Maximum Torque N m r p m 52 2 2800 kgf m r p m 5 32 2800 ft lb r p m 38 5 2800 Direction of Rotation Counterclockwise as viewed from the P T O shaft side Cooling System Forced air cooling Valve Arrangement Over2. 10 25 ADJUST GOVERNOR SYSTEM Governor system is centrifugal flyweight type Governor weight is installed into governor gear driven by crankshaft Governor weight movement is transferred to throttle lever via governor shaft and 1 lever ORS EH d f Engine speed is maintained at the constant lt A iy speed by throttle valve opening and closing operation in accordance with load condition 5 of engine 1 Push speed control lever all the way to the high speed position and fix it by tightening nut 2 Check that governor lever is pulled by governor spring and throttle valve is fully open 3 Turn governor shaft counterclockwise all the way and tighten lock bolt to secure the lever on the shaft 26 BLOWER HOUSING Attach blower housing to crankcase with control box commonly fixed Connect fuel pipes onto blower housing BLOWER HOUSING Front M6 x 14 Flange bolt 4 pcs Tightening torque 3 9 5 9 Nem 40 60 kgfecm Front 2 9 4 3 BLOWER HOUSING Side M6 x 18 Flange bolt 2 pcs M6 x 14 Flange bolt 2 pcs Tightening torque 2 9 4 9 Nem 30 50 2 2 3 6 46 11 27 FUEL PUMP and FUEL PIPE 1 Install fuel pump bracket onto 2 cylinder baffle FUEL PUMP M6 x 12 Flange bolt 1 pc Tightening torque 6 8 8 8 Nem FUEL FILTER 70 90 5 0 6 5 ftelb CONNECTE
3. pem N 2 Sees 8 pO wey A CHARGE ELECTRIC ao a Grn STARTER DELIVERY RETURN FUEL TANK 4 ELECTRIC FUEL FUEL FILTER AIR PRESSURE THROTTLE BODY PULSATION DAMPER FUEL REGULATOR IG COIL 1 R P M ECU Engine Control Unit IG COIL 2 R P M MAP SENSOR Manifold Air Pressure Sensor 15 6 THROTTLE BODY 6 1 SPECIFICATIONS This engine is equipped with Electronic Fuel Injection system Fl system integrated with ECU Engine Control Unit The FI system consists of throttle body 2 barrel ECU MAP Manifold Air Pressure sensor injector pressure regulator temperature sensor electric fuel pump and pulsation damper The fuel system is calibrated after careful testing for optimum all round performance including starting acceleration fuel consumption output power characteristics The throttle body monitors air and engine temperature at start up and performs the choke function automatically While the engine is in operation the throttle body monitors engine speed manifold air pressure and engine temperature to ensure proper engine performance 6 2 FUNCTIONS AND CONSTRUCTION 6 2 1 ELECTRIC FUEL PUMP The electric fuel pump is located below the throttle body and actuated by power from the DC battery The fuel flows from the tank into the fuel p
4. M6 BOLT AND PLUG CAP E WASHER ASSY 2270 P 6 BOLT AND TO THROTTLE BODY ASHER ASSY STEP 14 IGNITION 1 CYLIND COIL GROMMT PLUG CAP PLUG TERMINAL 2 CYLINDER SIDE ONLY SPARK PLUG CAP 0 ECU and KEY SWITCH HOSE CLAMP FUEL PIPE HOSE CLAMP d im CONNECTER UEL PUMP 3 HOSE CLAMP FUEL FILTER Parts to remove Remarks and procedures Parts Fasteners Regulator and Wire CP 1 Disconnect wire connector from regulator and then M6 x 12 Flange bolt 2 pcs remove regulator from 1 cylinder baffle 2 Remove temperature sensor from main bearing cover Tapping screw 1pc 3 Disconnect the wiring harness 1 injector 1 2 temperature sensor ignition coil 1 2 4 Disconnect the wiring harness 2 fuel pump ground warning lamp ignition coil ground Spark plug Take care the spark plug is hot just after stopping engine BPR5ES or BPR4EY STEP 16 M8 FLANGE NUT WIRING HARNESS p STEP 15 INTAKE MANIFOLD Bons CYLINDER REGULATOR BAFFLE 41 TO THROTTLE BODY ECU TAPPING TEMPERATURE SENSOR WIRING HARNESS 1 WIRING HARNESS 2 FUEL PUMP POWER GROUND INJECTOR 1 INJECTOR 2 y CONNECTER e TEMPERATURE 5 WARNING GRAY SO 27 SENSOR LAMP ev 2 P IGCOIL GROUND TO IGNITION COIL 82 BATTERY
5. Tightening torque 16 6 18 6 Nem 170 190 kgf cm 12 3 13 7 ftelb MUFFLER gt lt MUFFLER 3 Install Muffler cover onto Muffler M6 Flange bolt 6 pcs Tightening torque 6 8 8 8 Nem 70 90 5 0 6 5 6 243 32 FINAL CHECK Be sure to check loosen bolts and nuts and also electric wiring connections 33 ENGINE OIL Standard Option Refill engine oil and start the engine OIL GAUGE Engine oil will be lubricated oil passages and oil filter Check the engine oil level and refill again to the upper level of oil level gauge Oil Capacity 1 55 liter 0 41 U S gal NOTE Check the oil level with the oil gauge inserted Use SE API classification or higher grade engine oil UPPER LEVEL OIL GAUGE OIL GAUGE LOWER LEVEL UPPER LEVEL gt UPPER LEVEL LOWER LEVEL LOWER LEVEL 4 5 BREAK IN OPERATION An engine that has been completely overhauled by being fitted with a new piston rings valves and connecting rod should be thoroughly RUN IN before being put back into service Good bearing surfaces and running clearances between the various parts can only be established by operating the engine under reduced speed and loads for a short period of time While the engine is being tested check for oil leaks Make final carb
6. The fuel system is calibrated after careful testing for optimum all round performance including starting acceleration fuel consumption output power characteristics The throttle body monitors manifold air pressure and engine temperature at start up and performs the choke function automatically While the engine is in operation the throttle body monitors engine speed manifold air pressure and engine temperature to ensure proper engine performance For further information refer to page 16 section 6 THROTTLE BODY 3 4 DISASSEMBLY AND REASSEMBLY 4 1 PREPARATIONS AND SUGGESTIONS When disassembling the engine memorize the locations of individual parts so that they can be reassembled correctly If you are uncertain of identifying some parts it is suggested that tags be attached to them Have boxes ready to keep disassembled parts by group To prevent losing and misplacing temporarily assemble each group of disassembled parts Carefully handle disassembled parts and clean them with washing oil if necessary Use the correct tools in the correct way When disconnecting electric wirings be sure to hold and disconnect the connector housing 4 2 SPECIAL TOOLS No Special Tool is needed for disassembling and reassembling the engine For pulling off the flywheel universal type puller being popular in the market place as shown in the illustration is needed Description Parts number Flywheel puller for pulling
7. IGNITION COIL 1 a 2 TO THROTTLE BODY L SIDE WIRING COLOR copE 0 inside wiring color code Bik Black Gry Gray R Red Grn Green Wite 4 4 REASSEMBLY PROCEDURES DIFFERENCE 20 COOLING FAN Attach cooling fan onto flywheel M6 x 16 bolt amp washer 4 pcs px BOLT and SHER 4 pcs Tightening torque 6 8 8 8 Nem 70 90 kgfecm 5 1 6 5 ftelb 21 THROTTLE BODY 1 Replace the gasket of manifold with a new one and mount the throttle body on the tromi 2 MANIFOLD intake manifold BODY EA NC gt 2 Replace the gasket of throttle body with a CLEANER 5 new one and mount the cleaner adapter on ADAPTER the throttle body M6 FLANGE NUT 4pcs isa Tightening torque 2 6 8 8 8 Nem 70 90 WIRING WIRING 5 1 6 5 ftelb HARNESS 1 HARNESS 2 3 Connect the connectors from ECU to the injectors 22 IGNITION COIL and WIRE CP 1 Temporally fit ignition coil to crankcase Adjust air gap between ignition coil and flywheel using a thickness gauge and tighten bolts Ignition coil air gap 0 3 0 5 mm 0 012 0 020 in THICKNESS GAUGE IGNITION COIL M6 x 30 bolt amp washer 4pcs Tightening torque 6 8 8 8 Nem 70 90 kgf cm 5 1 6 5 ftelb Som 6 ce 2 Connect wiring from ECU to the primary terminal of ignition coil 3 Clamp the wiring harness with wire bands t
8. belt horizontally Disengage the load when starting the engine If no clutch is used use a belt tension pulley or the like 7 5 2 FLEXIBLE COUPLING When using a flexible coupling run out and misalignment between the driven shaft and engine shaft must be minimized Run out and misalignment tolerance are specified by the coupling manufacturer 249 8 TROUBLESHOOTING The following three conditions must be fulfilled for satisfactory engine start 1 The cylinder filled with a proper fuel air mixture 2 Good compression in the cylinder 3 Good spark properly timed to ignite the mixture The engine cannot be started unless these three conditions are met There are also other factors which make engine start difficult e g a heavy load on the engine when it is about to start at low speed and a high back pressure due to a long exhaust pipe The most common causes of engine troubles are given below 8 1 NO ENGINE OPERATION Phenomenon Possible causes Remedy 1 Poor connection of key switch wiring Check repair or replace 2 Wiring discontinuity between key switch and starter motor Replace 3 Wiring discontinuity between battery and starter motor Replace 4 Improper battery low capacity or discharged battery Charge or replace battery 1 Electric starter does not 5 Poor connection of battery terminal Check clean or replace operate 6 Starter magnetic switch faulty Check clean repair or repl
9. maintenance and inspection frequency of checks and repairs and operating cost all depend on the way in which the engine is installed Review the following instructions carefully for installing the engine 7 1 INSTALLING When mounting the engine carefully examine its position the method of connecting it to a machine the foundation and the method of supporting the engine When determining its mounting position in particular make sure that gasoline and oil can easily be supplied and checked the spark plug can easily be checked the air cleaner can easily be serviced and that the oil can easily be discharged 7 2 VENTILATION Fresh air is necessary for cooling the engine and burning the fuel In the case the engine is operated under a hood or in a small room temperature rise in the engine room can cause vapor lock oil deterioration increased oil consumption loss of power piston seizure shorter engine life etc making it impossible to operate the engine properly It is necessary therefore to provide a duct or baffle to guide cooling air to the engine to prevent recirculation of he hot air used for engine cooling and temperature rise of the machine Keep the engine room temperature below 50 C even in the hottest period of the year 7 3 EXHAUST GAS DISCHARGE Exhaust gas is noxious When operating the engine indoors be sure to discharge the exhaust gas outdoors If a long exhaust pipe is used in such a case the internal resis
10. re connect the grey wire to the oil pressure switch after troubleshooting with failure diagnosis system 8 10 2 INDICATION MEANS and PROCEDURE Key position Description Tune the key switch to the RUN position Oc l a Lightning 2 sec and go out forever Not see any problem NU 0 Lamp b Lightning 2 sec and go out 4 sec then lightning again There is some problem NU 9 Referto step2 ime Lamp a After the 4 sec the lamp repeats turning on and off EUN ETA Go out 4 sec OQ AND TANS N This sample failure code is 2 1 Two 2 turning on and off and go out 2 sec then turning on 0 4 sec After this go out 4 sec and repeat the code again b If there is another failure the lamp indicates continuity with new code Refer to step 3 26 Key position Description In case of another failure after the 4 sec the lamp repeats turning on and off This sample is failure code means 4 2 1 Xe SW SKE 3t CT AN Fore 4 turning off and go out 2 sec then turning on 0 4 sec After this go out 4 sec and repeat the code again If there is another failure the lamp indicates continuity with new code 8 10 3 FAILURE CODE Please refer to the following table for the failure diagnosis code Key position Failure code Possible causes 2
11. 1 Low voltage of battery Charging system failure Disconnecting or short circuit internal of throttle body between MAP sensor and ECU Disconnecting or short circuit between temperature sensor and ECU Disconnecting between fuel pump and ECU Disconnecting between fuel injector 1 and ECU Disconnecting between fuel injector 2 and ECU Disconnecting between ignition coil 1 and ECU Disconnecting between ignition coil 2 and ECU After starting the engine the above codes also will be indicated 9 MAINTENANCE AND STORAGE 9 1 DAILY MAINTENANCE Every day before operating engine check the following items MAINTENANCE ITEMS REMARKS 1 Clean away dust and chaff from engine Governor linkage is especially sensetive to dust 2 Check fuel leakage from fuel system If any retighten fasteners or replace necessary parts 3 Inspect for loose hardware and retighten if Loose bolts and nuts may come off and result in necessary breakage of other parts 4 Check oil level and add to full level 9 2 PERIODIC MAINTENANCE SCHEDULE Periodic maintenance is vital to safe and efficient operation of engine Check the table below for periodic maintenance intervals It is also necessary to conduct the maintenance and adjustments on the emission related parts listed below to keep the emission control system effective 1 Throttle body and 4 Air cleaner elements 8 Exhaust manifol
12. Ca SUBARU 72 Air cooled 4 cycle SUBARU MC uM Gasoline Engine SERVICE INFORMATION PREFACE This manual covers the service information trouble shooting procedures and so on of EH72 Fuel injection engine Careful observance of the instructions given herein will result in better safer and faster service work For more detailed instructions of disassembling and reassembling procedures please refer to the service manual for EH63 64 65 and 72 CONTENTS Section Title Page 1 SPECIFICATIONS Ie RR eatin tenets tad ur ta e Re idee 2 FEATURES v TTTT 3 DESCRIPTION OF FUEL 5 5 4 DISASSEMBLY AND 55 hrs 4 1 PREPARATIONS AND 50 5 4 2 SPECIAL TOOLS ox 84 gap he om ed Ue 4 3 DISASSEMBLY PROCEDURES 4 4 REASSEMBLY PROCEDURES 4 5 BREAK IN OPERATION vii esac ae bea We Phd we Seba dda dae ea 14 5 DIAGRAM or i ob De
13. I DU e eb aC E REP ee ta i ee ee s 15 6 THROTTLE BODY irre iet e er tr Re Xe does 16 6 1 SPECIFICATIONS o 4 Rb E docks tibet dew deed bx ei pee ie th 16 6 2 FUNCTIONS AND 5 2 22 2 rns 16 6 3 FUEL SYSTEM OUTLINE os ceeds ARR URS URGERE EU RU 17 6 4 FUEL SYSTEM TESTING AND DIAGNOSIS sssssse ele 17 T INSTALLATION MM 18 TA INSTALLING s we ha he ieee 18 T2 VENTILATION 2 2 503 224 dus che e c Ree asd ND RC ect e CR Ur cd cie a CR AR 5 18 7 3 EXHAUST GAS DISCHARGE ens 18 7 4 FUEL SYSTEM rb ERREUR Ad eR Ra e n RR RR NR eR RA Race RU 19 7 5 POWER TRANSMISSION TO DRIVEN MACHINES 19 8 TROUBLESHOOTING ko er ego Ede eee E bora Ue 20 8 1 NO ENGINE OPERATION ah eaters Oy ai ido on SIE OE ce ce VR S Reds 20 8 2 STARTING DIFFICULTIES e EXER ERE esa EGRE A RE 21 8 3 INSUFFICIENT OUTPUT ssssesee erre 22 8 4 OVERHEAT CASA RR RAE ted sa deh ges 22 8 5 ROUGH IDLING s 3er den ek cR EO d bed PE b drea ea eedem RE RE E Es 23 8 6 HIGH ENGINE OIL CONSUMPTION sssssee hes 23 8 7 HIGH FUEL CONSUMPTION
14. N By adopting the Engine Control Unit ECU incorporated inside the throttle body of electronic fuel injection system EH72 Fl has achieved very compact design which is same envelope size as carbureted engine to keep superb mountability for machineries USER FRIENDLY Excellent startability The newly developed electronic fuel injection system provides optimum fuel flow by sensing ambient temperature It realizes easy and surefire start up performance with no choke operation even in the low temperature Better response and acceleration The electronic fuel injection system offers an excellent running performance which are less subject to external circumstances such as changes of ambient temperature and atmospheric pressure This means no need any manual adjustment at high altitude such as changing main jet of carburetor 3 DESCRIPTION OF FUEL SYSTEM This engine is equipped with Electronic Fuel FUFEPRESSURE Injection system FI system integrated with REGULATOR a THR TTLE ECU Engine Control Unit DK BODY AY The Fl system consists of throttle body 2 barrel ECU MAP Manifold Air Pressure sensor injector fuel pressure regulator temperature sensor electric fuel pump and INJECTOR pulsation damper ECU Engine Control Unit CLEANER PULSATION DAMPER THROTTLE ADAPTER BODY AY C c ED Hh pe 2 ELECTRIC FUEL PUMP INTAKE MANIFOLD OIL FAIL WARNING LAMP OPTION TEMPERATURE SENSOR
15. R PULSATION DAMPER FUEL PUMP 2 Connect the wiring to the fuel pump 3 Connect fuel pipe between throttle body and fuel pump 28 AIR CLEANER and BREATHER PIPE 1 Connect breather pipe to air cleaner base 2 Fit air cleaner base onto throttle body M6 x 12 Flange bolt 3 pcs Tightening torque 6 8 8 8 Nem 70 90 5 0 6 5 16 3 Connect breather pipe to 1 cylinder head 4 Set air cleaner element along with urethane foam onto base 5 Install air cleaner cover with knob 29 OIL PRESSURE SWITCH 1 Install oil pressure switch onto adapter Oil cooler Tightening torque 5 9 9 8 Nem 60 100 kgf cm 4 3 7 2 ftelb NOTE Not to tighten excessively OIL PRESSURE SWITCH 2 Connect the wiring to the oil pressure switch 212 30 OIL FILTER Apply oil to O ring and install oil filter by tightening about 3 4 turns after attaching crankcase surface Tightening torque 9 9 14 7 Nem 100 150 kgf cm 16 3 19 8 ftelb NOTE Start engine after assembling and check for no oil leakage from oil filter 31 MUFFLER 1 Install Muffler bracket onto Cylinder head 8 x 20 bolt amp washer 2 pcs M6 FLANGE BOLT Tightening torque 16 6 18 6 Nem 170 190 kgf cm 12 3 13 7 ftelb 2 Install Muffler onto Muffler bracket and Cylinder head M8 SUS flange nut 4 pcs
16. Remedy 1 Throttle body 1 Low idling speed Adjust 2 Throttle body slow system passage clogged Check clean and replace 2 Intake system 1 Air mixing from connecting portion of air intake system Check tighten or replace gasket 3 Cylinder head 1 Cylinder head gasket faulty blow by Replace 4 Valve system 1 Improper valve clearance Adjust 2 Leakage from valve seat Adjust valve seat contact 3 Excessive clearance between valve stem and guide Replace 5 Ignition system 1 Weak ignition spark 8 6 HIGH ENGINE OIL CONSUMPTION Phenomenon Possible causes Check and replace spark plug 1 Oil leakage 1 Loosen drain plug Tighten 2 Drain plug gasket damaged Replace 3 Incorrect oil filter fitting Repair 4 Loosen main bearing cover bolts Tighten 5 Main bearing cover gasket damaged Replace 6 Crankshaft oil seal damaged Replace 2 Oil dilution 1 Piston oil ring faulty Replace 2 Piston rings seizure wear or poor contact Replace 3 Excessive wear of piston and cylinder Replace 4 Excessive wear of valve stem Replace 5 High oil level Adjust oil level 6 Breather faulty 23 Repair or replace 8 7 HIGH FUEL CONSUMPTION Phenomenon Possible causes Remedy 1 Fuel system 1 Throttle body faulty Check or replace 2 Pulsation dam
17. ace 7 Starter motor faulty Repair or replace 8 Crankshaft seizure Check repair or replace 9 Seizure between piston and cylinder Check repair or replace 1 No fuel Refill 2 Electric starter operates but engine does 2 Poor connection or discontinuity of ignition system wirings Check repair or replace not start 3 Electric starter faulty Repair or replace 20 8 2 STARTING DIFFICULTIES Phenomenon Possible causes Remedy 1 Low engine speed at starting 1 Battery discharged Charge battery 2 Poor connection between battery and starter motor Clean or repair 3 Poor connection between battery and ground Clean or repair 4 Electric starter faulty Repair or replace 5 Improper engine oil Replace with recommended engine oil 2 Ignition system malfunction Spark plug Improper spark plug gap No insulation Carbon deposits Adjust Replace Clean Ignition coil No insulation or discontinuity Poor connection or discontinuity of ignition code Check with failure diagnosis system Replace Repair or replace Improper air gap between ignition coil and flywheel Adjust 3 Fuel system malfunction 1 No fuel in fuel tank Refill 2 Fuel pump clogged 3 Fuel hose clogged or pinched Clean or replace Clean or replace 4 Air mixing into fuel lines Check and adjust connecting por
18. d if internal parts 5 Spark plug applicable 2 Cold start enrichment 6 Magneto or electronic 9 Hoses belts connectors system if applicable ignition system and assemblies 3 Intake manifold if 7 Spark advance retard applicable system if applicable The following maintenance schedule is based on the normal engine operation Should the engine be operated in extremely dusty condition or in heavier loading condition the maintenance interval must be shortened depending on the contamination of oil clogging of filter elements wear of parts and so on 28 Periodic Maintenance Schedule table Every Every Every Every Every Maintenance Items 8 hours 50 hours 200 hours 500 1000 Daily Weekly Monthly hours hours Clean engine and check bolts and nuts Daily Check and refill engine oil Refill daily up to upper level NER Change engine oil Note 1 Q Initia 20 hours Every 100 hours Check battery electrolyte fluid level Every 100 hours Clean spark plug Clean air cleaner Clean spark arrester Optional part Replace air cleaner element Clean fuel strainer Clean and adjust spark plug and electrodes rer Remove carbon from cylinder head Clean throttle body Clean engine base oil pan Check and adjust valve clearance Replace fuel lines Yearly Note 1 Initial oil change and oil filter replacement should be performed after 20 hours of operation Thereaf
19. e special screw from the spark arrester and remove the spark arrester from the muffler Clean the spark arrester screen Use a brush to remove carbon deposits from the spark arrester screen Be careful to avoid damaging the screen The spark arrester must be free of breaks and holes Replace the spark arrester if it is damaged Install the spark arrester and muffler protector in the reverse order of disassembly 230 9 4 ENGINE STORAGE 1 Drain fuel from fuel tank and run the engine until there is no fuel left 2 Change the engine oil and perform the daily maintenance items above mentioned 3 To prevent rust in the cylinder bore apply oil through the spark plug hole and turn the crankshaft several turns by hand Reinstall the plug 4 Turn the crankshaft by hand and leave it where the resistance is the heaviest 5 Clean outside of the engine with oiled cloth 6 Put a plastic cover or the like over the engine and store the engine in dry place Si ISSUE EMD ES6790 Ga SUBARU FUJI HEAVY INDUSTRIES LTD INDUSTRIAL PRODUCTS COMPANY 4 40 ASAHI KITAMOTO SHI SAITAMA 364 8511 JAPAN TEL 81 48 593 7798 FAX 81 48 593 7946 Printed in Japan http www subaru robin jp 2009 08
20. eat contact Repair or replace 6 Valve stem seizure Repair or replace 7 Improper valve clearance Adjust 2 Ignition system malfunction 1 Spark plug faulty 2 Ignition coil faulty Replace Replace 3 Improper air gap between ignition coil and flywheel Adjust 4 Magneto demagnetization Replace 3 Fuel system malfunction 1 Throttle body clogged Check and replace 2 Improper fuel pump operation Check and replace 3 Fuel strainer or fuel hose clogged Clean or replace 4 Air mixing into fuel lines Check and adjust connecting portion 5 Improper gasoline or water infiltration Replace 6 Improper pulsation damper operation Replace 4 Low intake air volume 1 Air cleaner clogged Clean or replace 2 Throttle valve faulty 8 4 OVERHEAT Phenomenon Overheating Possible causes 1 Cooling air flow obstructed at inlet or cylinder baffle portion Repair or replace Clean 2 Improper engine oil Replace 3 Lean air fuel mixture Check and replace throttle body and pulsation damper 4 Excessive back pressure of exhaust system Check clean or replace 5 6 Over load Clogged oil cooler Change to rated load Check and clean or replace 7 Loosen or missing spark plug cap 222 5 Check and connect properly 8 5 ROUGH IDLING Phenomenon Possible causes
21. erature sensor that measures engine temperature and connects fuel injectors ignition coils electric fuel pump pressure switch and warning lamp The ECU uses this input to adjust to engine various conditions and monitors for failure diagnosis 6 2 5 CHOKE SYSTEM The throttle body monitors air pressure and engine temperature at start up and performs the choke function automatically The choke system automatically adjusts for easier start of the engine in all weather conditions 6 3 FUEL SYSTEM OUTLINE Throttle Body Assy Fuel Pressure Regulator M A P Sensor Air Cleaner PULSATION DAMPER 0 3kgf cm2 Engine Temperature Ignition Pulse sensor PULSATION TANK FILTER PUMP _ DAMPER gt INJECTION to FUEL RETURN PIPE _ COMBUSION 6 4 FUEL SYSTEM TESTING AND DIAGNOSIS Most fuel system malfunctions occur when the fuel air ratio of the mixture is not correct This is usually caused by clogged fuel filters air passages fuel passages or by variations in the fuel level To get the best possible performance from the throttle body make sure that the fuel feed and air feed passages are free so air and fuel can flow freely through them The procedure for inspecting the fuel system is described below Run all system tests with a full tank of fresh clean fuel 17 7 INSTALLATION Engine life ease of
22. head Valve OHV Lubrication Full pressure type with oil Cooler Automobile engine oil SAE 20 30 or 10W 30 Lubricant Class SE or higher Capacity of Lubricant L U S gal 1 55 0 41 Throttle body Electronic Fuel injection Fuel Automotive unleaded gasoline Fuel Feed System Electronic Fuel pump Ignition System Flywheel Magneto Solid state Spark Plug BPR5ES NGK BPRAEY NGK Charging Capacity 12 15 or 12 30 Option Starting System Electric Starter Governor System Centrifugal Flyweight type Air cleaner Double Element type with out muffler and control box 46 101 3 Dry Weight with STD muffler and control box 51 5 113 4 Dimensions with out muffler and control box 317 X477 X480 12 5X 18 8 X 18 9 LXWXH mm in with STD muffler and control box 464 X 499 X 480 18 3 19 6 X 18 9 Specifications are subject to change without notice 2 FEATURES EH72 has been developed as a high performance model equipped with the electronic fuel injection system HIGHER POWER OUTPUT has been achieved by increasing inlet air volume with larger venturi bore ENVIRONMENTALLY FRIENDLY By optimizing the fuel injection management EH72 Fl has achieved approx 11 improvement on the fuel efficiency as well as drastic reduction on the exhaust emission Therefore EH72 FI comply with CARB Tier 3 Emission Regulations in the USA COMPACT DESIG
23. n of ignition system wirings Check with failure diagnosis system and connect properly 2 Fuel system 1 Lean or rich air fuel mixture Check and replace throttle body 2 Clogged throttle body Check and replace 3 Throttle body faulty 4 Pulsation damper faulty Check and replace Check and replace 5 Fuel pump faulty 6 Improper gasoline or water infiltration Check and replace Replace 3 Engine core componets 1 Valve heat deterioration or improper valve adjustment 2 Valve spring deterioration Adjust or replace Replace 3 Low compression 25 Check adjust or replace 8 10 DIAGNOSIS CODE This engine has the failure diagnosis system to know that low voltage of DC battery and each wiring whether disconnecting or electrical short circuit The ECU monitors engine various conditions for the system when tune the key to the RUN ON position START cranking or after start the engine However this is required the warning lamp or a lamp for DC12V to indicate of the failure code The warning lamp and so on is prepared as optional 8 10 1 HOW TO OPERATION When troubleshooting with the failure diagnosis disconnect the grey wire to oil pressure switch If the wire will be not disconnected the lamp will be lightning cause of the engine stopped and no oil pressure If there is failure the components wiring the warning lamp repeats turning on and off Finally
24. o the intake manifold 23 GOVERNOR LEVER 3 SHAFT Attach governor rod and rod spring T between governor lever and throttle body GOVERNOR throttle lever and insert the governor lever LEVER to governor lever shaft Tighten locking bolt temporarily GOVERNOR GOVERNOR THROTTLE LEVER ROD Turn the rod holder counter clockwise and fix it Then hook the rod IOM ROD SPRING ROD HOLDER spring as shown on the diagram GOVERNOR ROD ROD HOLDER 24 SPEED CONTROL LEVER 2 1 2 control bracket onto intake NUT STOP PLATE manitola lt 5 SPRING WASHER 2 Attach return spring spacer friction washer wing nut etc to speed control lever as shown in the ilustration 3 Connect governor spring to governor lever FRICTION 6 FLANGE and speed control lever BOLT E INTAKE MANIFOLD THROTTLE BODY CLEANER ADAPTER BRACKET UNIT S Ze o S speed control CGA GOVERNOR c m 11 Fitting location of governor rod and governor spring GOVERNOR a il 2 d v b e d a Je GOVERNOR 5 FULL CLOSE FULL OPEN ROD 4 A 3 LOCK NUT B ADJUSTING I SCREW
25. off the flywheel 228 95001 17 Flywheel puller with bolt 4 3 DISASSEMBLY PROCEDURES DIFFERENCE Parts to remove Remarks and procedures Parts Fasteners Choke lever Choke lever not applicable Governor rod 1 Remove the governor rod spring from rod holder 2 Pick up the rod holder and remove the governor rod See Fig 4 1 3 Remove the governor rod and the rod spring from the governor lever 4 Loosen the bolt and remove the governor lever M6 bolt and washer 1pc T Governor GOVERNOR LEVER 5 ROD HOLDER o o o o a U GOVERNOR ROD ROD SPRING GOVERNOR ROD Fig 4 1 Parts to remove Remarks and procedures Parts Fasteners Throttle body 1 Disconnect the two connectors from ECU under the throttle body 2 Disconnect the two connectors from the two injectors on the throttle body 3 Remove the nuts adapter and throttle body from the M6 Flange nut 4pcs intake manifold STEP 10 CLEANER ADAPTER CONNECTER CONNECTER INJECTOR INJECTOR GOVERNOR LEVER amp M6 FLANGE NUT Step Parts to remove Remarks and procedures Parts Fasteners Fuel pump 1 Disconnect the connecter places from fuel pump wiring harness 2 M6 x 12 Flange bolt 1 pc 2 Remove fuel pump ASSY and detach bracket 1 IGNITION COIL PLUG TERMINAL
26. per faulty Check or replace 3 Fuel pump faulty Check or replace 2 Engine core components 1 Low compression Check or repair 2 Over cooling 8 8 DETONATION Phenomenon Possible causes Check and adjust load and or engine speed Remedy Ignition system malfunction Fuel system malfunction 1 Poor connection of ignition system wirings Check with failure diagnosis system and connect properly 2 Improper or damaged spark plug 1 Lean or rich air fuel mixture Clean or replace Check or replace throttle body 2 Throttle body damaged Check or replace throttle body 3 Fuel lines clogged or damaged Clean or replace 4 Air mixing from connecting portion of air intake system Connect properly or replace gasket Cylinder head 1 Carbon deposit in combustion chamber Remove and clean 2 Cylinder head gasket faulty blow by Replace Valve system 1 Improper valve clearance Adjust 2 Valve heat deterioration Replace 3 Valve spring deterioration Replace 4 Improper valve timing 224 Adjust 8 9 ENGINE MISFIRE Phenomenon Possible causes Remedy 1 Ignition system 1 Improper spark plug gap or damaged electrode Cealn adjust or replace 2 Ignition coil faulty Replace 3 Damaged ignition system wirings Check with failure diagnosis system and replace 4 Poor connectio
27. tance increases causing loss of engine power Thus pipe inside diameter must be increased in proportion to exhaust pipe length Exhaust pipe Less than 3 m long pipe inside diameter 30 mm Less than 5 m long pipe inside diameter 33 mm 18 7 4 FUEL SYSTEM When the fuel tank is mounted remote position from the engine the height from the bottom of the fuel tank to the fuel joint of the throttle body should be 500 mm and less The bottom of the fuel tank can be up to 400 mm below the throttle body Position the fuel tank carefully because when it is low fuel is not fed to the throttle body and when it is high it can cause high pressure in the throttle body then fuel rich and high fuel consumption When piping the fuel the hose should be as short as possible and attention should be paid to heat transmission size bending and leakage at hose joints and so on Care should also be taken to prevent air lock and vapor lock It is required that return piping to the fuel tank from the fuel pressure regulator on throttle body 7 5 POWER TRANSMISSION TO DRIVEN MACHINES 7 5 1 BELT DRIVE Take the following notes into consideration V belts are preferable to flat belts The driving shaft of the engine must be parallel to the driven shaft of the machine The driving pulley of the engine must be in line with the driven pulley of the machine Install the engine pulley as close to the engine as possible If possible span the
28. ter change oil every hundred 100 hours and replace oil filter 200 hours Before changing oil check for a suitable way to dispose of old oil Do not pour it down into sewage drains onto garden soil or into open streams Your local zoning or environmental regulations will give you more detailed instructions on proper disposal Overhaul engine Note 2 Note 2 As to the procedures please refer to the Service Manual or consult your nearest service dealer Note 3 More frequent oil changing oil filter replacement and air cleaner service on replacement may be necessary depending on operating conditions This would include dusty environment high ambient temperature heavy engine loading 29 9 3 SPARK ARRESTER OPTIONAL In a dry or wooded area it is recommendable to use the product with a spark arrester Some areas require the use of a spark arrester Please check your local laws and regulations before operating your product The spark arrester must be cleaned regularly to keep it functioning as designed A clogged spark arrester Prevents the flow of exhaust gas e Reduces engine output e Increases fuel consumption Makes starting difficult If the engine has been running the muffler and the spark arrester will be very hot Allow the muffler to cool before cleaning the spark arrester How to remove the spark arrester 1 Remove the flange bolts from the muffler cover and remove the muffler cover 2 Remove th
29. tion 5 Improper gasoline or water infiltration 6 Throttle body Poor connection or discontinuity of throttle body ECU Clogged or damaged Improper operation of throttle valve Replace Repair or replace Check with failure diagnosis system Clean or replace Check and adjust or replace 7 Poor connection of fuel pump wiring Check with failure diagnosis system 8 Improper pulsation damper Replace 9 Improper temperature sensor Check with failure diagnosis system and replace 4 Engine core components malfunction 1 Insufficient tightening of cylinder head bolts Check and retighten 2 Wear of piston piston ring and or cylinder Repair or replace Repair 4 Valve seizure Repair 3 Improper contact of valve and seat 5 Improper valve clearance Adjust 6 Intake manifold gasket leakage Retighten intake manifold bolts or replace gasket 7 Throttle body gasket leakage Retighten cleaner adapter flange nut or replace gasket 8 Insufficient tightening of spark plug 21 Retighten 8 3 INSUFFICIENT OUTPUT Phenomenon Possible causes Remedy 1 Low compression 1 Loosen spark plug Retighten or replace gasket 2 Cylinder head gasket leakage Retighten or replace gasket 3 Piston ring s seizure or wear Replace 4 Piston or cylinder wear Repair or replace 5 Incorrect valve and s
30. ump When the fuel pump is actuated by DC battery the fuel is pressurized by the pump and pushed into the throttle body pressure port 6 2 2 FUEL PRESSURE REGULTOR After the fuel pressure port is a diaphragm type fuel pressure regulator The fuel pressure regulator relieves the throttle body of any excess fuel pressure and returns excess fuel pressure back to the fuel tank through the fuel pressure return pipe 6 2 3 FUEL INJECTOR The throttle body pressure port feeds fuel at a regulated pressure to the fuel injectors Fuel is metered by the fuel injector that is actuated electronically by ECU The fuel is injected into the throttle bore and mixed with air from the air cleaner 6 2 3 ENGINE CONTROL UNIT ECU The ECU engine control unit on bottom of the throttle body is powered by DC battery The ECU monitors engine conditions such as engine speed air pressure and engine temperature With these inputs the ECU actuates the fuel injector to ensure the fuel air mixture is of optimum concentration and is fed into the combustion chamber of the engine at the correct timing When engine speed reached to 4 200 rpm the ECU cuts fuel to prevent over speed The ECU also controls the low oil sensor system and monitors voltage of DC battery and each wiring whether disconnecting or electrical short circuit 16 6 2 4 WIRE HARNESS The wire harness for the Fl system connects key system components to the ECU The FI wire harness contains a temp
31. uretor adjustment and regulate the engine operating speed EH72 FI Engine speed rpm Time minute 2500 10 No Load 3000 3600 7 5kW 10 0HP 3600 14 9kW 20 0HP 3600 14 5 BLACK WHITE Bik Blk d OIL FAIL WARNING LAMP RED ELECTRIC OPTION YELLOW FUEL PUMP GREEN GRAY Grn R Gry 5 Bik w THROTTLE Covering Blk Bik BODY OIL Blk GEEANER PRESSURE 2 CYLINDER SIDE Wiring harness 2 ADAPTER R SWITCH T R lt Blk 914 Blk Covering Gry 1 CYLINDER SIDE 177 Covering BIk Wiring harness 1 Grn E L1 E 1 Grn R t pi o OPTION Covering Gry c M IGNITION IGNITION ll COIL 2 SPARK COIL 1 SPARK fff i 2 PLUG PLUG CYLINDER CYLINDER he KEY SWITCH SIDE SIDE 5 iem OPTION TEMPERATURE BODY SENSOR REGURATOR
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